Max value in cell - overflow into adjacent cell

I want to have a field that maxes out at 2400 minutes (40 hours) and then filters the overflow into another cell.

I found this solution in another thread (post5560206), but for some reason I can't get the code to run properly (at all). Nothing changes when I enter a number to the minutes column on the user sheet.

Can someone maybe take a look at this and see if they can identify how I am misapplying the code? I suspect it has to do with the formula in D2, but I don't know. Not sure how I can work around that...

Here's how I have it set up: (test file attached)

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